text:
What is the flight that returned to base after dumping fuel due to toilet issues?
From this post I got to know one of the flight has emergency landed due to LAV tank full and Lavatory was In-operative.
Can someone please share the flight details that made emergency landing due to Lav in-operative or Lav is full? This will help in my study (white paper publish).

What "flight details" do you want? The flight number? It isn't unheard of for an aircraft to get diverted for lavatory issues, there are quite a few examples in the past few years (almost all of them involve Shannon Airport, Ireland for some reason).

I want details like which date the incident happened? Which Airliner?

I'm going to be a bit lazy and only point you in the right direction (sorry):
The Aviation Herald website is a simple, yet excellent source of aviation "occurences". There is a search tool at the top of the page, here is a link to a sample search I did using word lavatory:
Avherald.com search with word lavatory
...and below is a sample report picked from the results of the aforementioned search.

Incident: Jet2.com B738 near Cork on Aug 4th 2019, lavatory issues
By Simon Hradecky, created Monday, Aug 5th 2019 21:46Z, last updated Monday, Aug 5th 2019 21:46Z
A Jet2.com Boeing 737-800, registration G-JZBC performing flight LS-167 from Glasgow,SC (UK) to Lanzarote,CI (Spain), was enroute at FL360 about 90nm south of Cork (Ireland) when the aircraft turned around due to problems with the lavatories and diverted to Manchester,EN (UK) for a safe landing on runway 23R about one hour later. A passenger reported toilets were leaking water flooding the aircraft. The airline reported the aircraft diverted to Manchester to permit maintenance to service the toilets. A replacement Boeing 737-800 registration G-GDFV reached Lanzarote with a delay of 3.5 hours.

Searching the avherald.com database with relevant words will give you a plethora of cases for your white paper.


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Where to find NACA 65-110 Airfoil?
I'm working on a research project regarding the Bell XS-1, which used the NACA 65-110 airfoil. I haven't been able to find any data on this airfoil, and I'm wondering if anyone knows where I could?

Google "NACA 65-110" and the first entry is airfoiltools.

But there is not a 65-110 in airfoiltools. That's the issue.

Or is the 64- the same?

No, that's not the same as 65-110. The first digit after the 6 is the distance of the minimum pressure area in tenths of the chord.

@MD88Fan Apparently I am unable to read.) Sorry. 64- is similar but not exactly 65-. You didn't state what data you were looking for. Worst case you can download Xfoil (which was used make this database) and generate the 65-, though there is a learning curve.

strong textAt this webpage you can find the information about the Naca 65-110 airfoil.
- http://www.pdas.com/sections6.html

Link-only answers are discouraged because links can change over time.

The NACA airfoils are all designated by a math formula, pop in the variables (65-110) and out comes the shape. 4-digit series 5-digit series and the "6" series are the most popular.(all with standard or modified versions) So all you need is the 6 series formula and a spreadsheet.
The 6 series formula produces what are commonly called laminar-flow or critical-flow designs, they tend to avoid sharp changes in pressure. Laminar flow is only achievable with very smooth construction(no rivets or seams) and good clean flight conditions(bugs and dirt cause much more turbulent flow) However the same basic design due to the mild changes in pressure also have mild changes in local flow speed and so they also work well at increasing the critical mach number which is useful for high-speed subsonic aircraft like the 747-8. (as well as controlling the position of the shockwave when it does form)

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


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Why do most ARFF trucks tend to be so angular?

玄史生, CC0, via Wikimedia Commons
I've been looking at various types of ARFF (aircraft rescue and firefighting) apparatus, and while some rapid-response vehicles do appear to be more conventional, most full-size ARFF apparatus tend to have very pointy or curvy front (and sometimes back) ends. I'm curious why ARFF apparatus, especially those at larger airports, tend to be so wildly different from typical Type 1 and Type 2 fire engines.

While the upper portion design enables better visibility, the lower part design is also purposeful:
ARFF needs to be at least somewhat offroadable, as the plane in distress may not have stopped on paved surface. This necessitates the higher ground clearance and steep entry and exit angles. As mentioned in the articles in Quiet Flyers answer, ARFFs are all wheel drive for the aforementioned reason.
The "pointy" and elevated nose of the truck also assists in case the vehicle needs to plow through a foam batch. The foam is diverted under the vehicle instead of rising up along the nose onto the windscreen and hampering visibility.

In addition to the need to travel off road and/or through fences most ARFF vehicles are small batch or even bespoke productions. If you look at special use farm or industrial machinery you will see similar appearance where the design uses structures that can be fabricated from sheet and bar stock, without needing special purpose dies or jigs to make aesthetically pleasing complex curves - think of the shapes you could assemble from paper with scissors and tape.
The vehicle in the photo for example uses three straight beams to make up the wheel arch, and while the crew cab area is curved, most segments only curve in one axis so can be rolled on general purpose equipment without special purpose jigs or dies.

Good points here. As small batch products, ARFFs are stupid expensive, so all measures to cut costs wirhout jeopardizing functionality are used.

Also gets a big truck into a small garage.  Also roller side doors and equipment on trays call for flat sides

One important difference is that in an Airport Rescue and Fire Fighting (ARFF) truck, an operator may be operating a nozzle (which may be on a boom) from inside the cab, which may at times be positioned very close to the burning aircraft, and so the operator needs good visibility in many directions, including upwards.
Here are a few links of interest that describe some of the special features of ARFF vehicles:
https://www.oshkoshairport.com/experience/airport-products-blog/arff-trucks-vs.-municpal-trucks-whats-the-difference
https://www.arffresource.com/2018/12/07/anatomy-of-an-arff-truck/#gref
https://www.fireapparatusmagazine.com/fire-apparatus/latest-arff-apparatus-designs-stress-safety-quick-attack/#gref

One minor factor: while ARFF vehicles need to be fast when they are called into action, aerodynamics plays (most probably) no part, or a very small, part in their design.
The main purpose of the depicted fire-fighting vehicle is fighting fires. If they burn an additional gallon when they speed to the emergency scene, that does not matter in terms of their operational cost.
These vehicles aren't your run-of-mill road trucks which manage to run a six or seven digit number of miles/kilometers in their lifetime.

Yes, MPG hardly matters when they don't leave the airport grounds (unless the plane does). I would imagine if you had to haul one interestate, you'd flatbed it.

Most of these vehicles aren't even properly registered to be driven on roads. In Germany, when there were bigger fires outside of airports and the airport fire department assisted, most of the times those vehicles had to be accompanied by police cars.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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Is it worth it taking flying lessons even though I can't commit to regular lessons right now?
I can’t commit to flying on a regular basis right now. I’m close to a Class B airport with a flight school. There’s a C150 for 100/hr and a Zlin 242 for 160/hr. Instruction is 50/hr. There is, surprisingly, only one cheaper option nearby, and the price difference is small, so the closer option of the two is better. I’ve been studying the AFH, PHAK, and FAR/AIM, so I know my stuff. I’ve not yet taken ground school. I can’t commit to flying regularly right now. Is it still worth taking some lessons? I’d like to solo on my 16th birthday, so accruing hours is important. Should I wait until school is out and I can fly more regularly, or should I just go for it?

What do you mean by regularly?  I mean at one extreme there's a fixed schedule, just like a school class, when you go X times a week at the same time, for however many weeks it takes.  At the other you go whenever you have the time & money, which depending on your circumstances could mean long gaps between some lessons.  And what's your ultimate goal?  Do you want to fly for a living, or just for fun?

Look into student loans.  When you are ready to commit, money should be no object, but make sure you look into what pilots get paid every step of the way and perhaps fine tune your career goal.  A few lessons before you take the plunge certainly would not hurt your chances, and would enable you to visit several flying schools to pick the one you like best.

We have a couple of (maybe) related questions: here, here. This is a good question, but "should I?" or "is it worth it?" questions may not fit well here because they're often subjective, or they depend a lot on your personal situation and resources.

Is the flight school with the Cessna 150 at the Class B airport? Which airport? That is surprising. I would caution against taking lessons at the Class B airport. You will be paying rental and instruction rates by the hour. At a busy Class B airport, you might spend a lot of time on the ground with the prop spinning just waiting for clearance to takeoff. Also, Traffic Pattern work and landing practice probably won’t be allowed except for late late at night. You will probably also have to leave the airspace to practice maneuvers. All of this eats up time and money.

Look for a flight school at a slow Class C or D airport. Practice entering the Class B airspace. But, save your actual flights to the actual Class B airport for your night landings. This would be a better use of time and money.

I'll try to address the questions above:
@jamesqf - Regularly being scheduled lessons at the same time each week. That works better for me, and I plan on flying for a living.

@RobertDiGiovanni I've looked into them. I'm not sure if I'll take one, but I'm definitely looking at AOPA scholarships. Visiting several schools is a good plan, I'll look into that.

@DeanF. The school IS at the Class B airport. KBWI has a GA/bizjet only runway, and taxi time is short. There are several other airports (towered and non-towered) that would definitely do pattern work, and they're close enough that flying to them is fine. I'll probably at least take a few lessons at BWI to see if the time on the ground is an issue, if it is, there are other options, but the convenience of BWI is hard to beat.

I can't see that it would cause any harm.  It might be a waste of money but anyone who drives a 50,000 car just threw in the bin 48,000.  Every living person in the US seems to waste ~ 2000 a year on Dunkin Donuts.  (About 7 a day.)  Every time you spend 100 to go to the movies it is a "waste" of money.   Seems like a fantastic idea to me, and while "an entertainment expense" could there be a better way to spend it??

I would say no. Flying is something that requires practice, you can't do it piecemeal. Once you can commit the time and money, go for it!
It's a very rewarding skill but like most of those, it requires maintenance in the form of regular practice. If you can't do that, I wouldn't get started.

That echoes what I've been seeing. I'm thinking I might do one or two just for motivation and to make sure I want to move forward, but I'll be saving up for sure.


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Why hasn't the US military performed aftermarket modifications on certain aircraft?
The US military emits more CO2 annually than several countries. Winglets have been proven to work well in the commercial sector to reduce fuel burn, therefore reducing both CO2 emissions and fuel cost. The US military doesn't really lack research or production/modification capability, so why have winglets not been installed on non-fighter/attack aircraft? (Think C-130, E-3, KC-135...) They would reduce CO2 emissions and fuel costs, so why not implement them?

I don't think they care that much about cost or carbon footprint, but any improvement in fuel efficiency improves range, which they do care about, so good question...

Winglets are definitely not proven to reduce fuel burn. If you are designing a new aircraft, just make the wing appropriate span, that's most efficient. Winglets only improve things when there is a desire to use shorter wingspan—usually when scaling up existing design to keep the same wingspan as previous generation either to avoid larger redesign of the wing, or to make sure the new aircraft fits in the slots designed for the older one. When the plane isn't enlarged, there is rarely reason to add winglets.

Winglets reduce wingtip vortices (induced drag). If you have less drag, you need less power to go the same speed. If you use less power, you burn less fuel. Therefore, winglets reduce fuel burn.

https://medium.com/war-is-boring/small-winglets-could-save-the-u-s-air-force-big-on-fuel-11af2a8f2c79         Lockheed Martin already have OEM approved aero modifications for C-130 and C5 including winglets, fuselage microvanes, and automated deflection of control surfaces to adjust wing loading. The issue is bit about not wanting to reduce CO2 or make savings, it’s about capital costs of upgrading vs any future savings, loss of capability while these aircraft are in being upgraded, and the effect these mods will have on tactical activity such as airdrop which will require costly T&E.

If you really want this to happen, contact your congress-person, who is hopefully on the armed services committee, and convince them to formulate a bill to help save the environment to support this. Good luck with that.

I think the main reason is that many of these planes were produced before winglets were common
Look at a list of USAF planes and see what years each one were produced (I am not including every plane, but most of the common ones)

C-5: 1968–1973, 1985–1989
C-17: 1991-2015 (has winglets)
C-130: 1954-present
E-3: 1977-1992
KC-10: 1979–1987
KC-46A: 2013-present (does not appear to have winglets, even though recent)
KC-135: 1955–1965

But when you look at this story about winglets, there is the sentence

The first 747-400 was delivered to Northwest Airlines in 1989, the
first commercial aircraft with proper winglets.

So for the most part you are talking about adding winglets to an existing airframe, rather than aircraft with winglets as part of the design.  This increases the expense of adding winglets, which reduces their cost-effectiveness. Look at this article on modifiying the B-52 to use four modern engines and the problems with that (not all of these would apply to winglets).

Right. I understand that most of the US fleet was built prior to winglets being a big thing, but the question is why they haven't been implemented with aftermarket modifications.

Aftermarket modifications that affect aerodynamic stability would likely have to go through a certain amount of testing & certification, which isn't free, and is likely just not cost-effective when spread over a small number of planes. Consider: KC-46A (related to 767 but not identical, so you can't just transplant parts from one to the other) planned production 179 vs. 767 over 1,200 produced and more on order.

All the discussions of engineering difficulties and cost-effectiveness are valid arguments but based on my USAF career in program offices and in operating commands, including 4 years in TAC, it boils down to money and priorities.
Once the a/c is operational the program office is concerned with sustainment. They need to provide the engineering, tools, and materials needed to keep the planes combat ready. In addition to providing spares to the operating units, they are also responsible for depot level maintenance. They have a constrained budget and the priorities are set by the operators.
Spare parts are driven by in-field failures. Safety related issues take top priority. Service life extension becomes a concern on older a/c. And the operators have a wishlist of upgrades they would like.
The operator’s top priority is being mission capable. The wishlist will be things that keep the planes operational or improve its ability to perform its mission. There’s never enough money or time to get everything on the wishlist. So the list is a rough plan that projects out 10 years or so. It gets updated every year when they can lock down what they will do next year.
So the marginal increase in fuel economy from adding winglets never comes close to the top of that priority list. In addition to the direct costs of a large mod such as winglets, there is the operational cost of having the a/c spend an extra week in the depot. If a squadron has 24 a/c, that week in the depot equates to almost 6 months the squadron will be short an a/c. That’s a big hit to operational readiness.
When we were retrofitting GPS to the entire AF fleet in the 90’s it was a constant battle to get the operating commands to give us the time in depot to do the upgrades. They wanted the a/c back ASAP. It was about a 10 year effort and it took Congress threatening to pull upgrade funding for any aircraft that wasn’t GPS equipped after a cutoff date.
Any significant upgrades are usually addressed in the development of the replacement a/c. But even that will go through numerous trade offs to (try to) meet schedule and budget.

The wonderful world of weapons systems supply chain and logistics... it's my world right now, and this is spot on.

They have.
For example, look at the wingtips of the P-8. They don’t look like the commercial variant (because the commercial variant will snap off if you hang out in icing conditions for hours), but the wingtips it has essentially work the same way.
In general though, the answer to your specific question is that there is no “aftermarket”. Air Force and Army each rely almost entirely on the OEM for engineering design work the Navy does to a lesser extent, and no service has a good, recent record of in-house metal bending.

True! I hadn’t considered the P-8. However, with the KC-135 fleet, I think it could be done to have Boeing or LM or someone similar build a winglet kit for guard/reserve/active units to install.

@MD88Fan why do you think that, and what what advantage do you think it would provide? C-130 is under a PBL with LM, and is run out of a USAF program office. How do you envision that contract being structured?

Winglets work by using the span-wise air flow around the wing tip to generate forward 'lift'. This airflow is highly dependant on the angle of attack, so the winglet needs to be designed for a specific condition or it just adds weight and drag.
Airliners spend almost all their time at cruise height and speed while loaded, so it's possible to design a winglet that works for that case. Military aircraft have to operate in a wider range of conditions, and the improvement in cruise performance might not be worth the reduction in loiter time.
It might also help to consider using the weight of a winglet to just extend the wing. That would reduce wing-tip losses at all speeds, allow the plane to fly higher and reduce take-off and landing speeds. Why isn't it done? Because the designer has already worked out the optimum aspect ratio, and improving performance in one area would reduce it in another.

True, but the question was about support aircraft (transport, tanker, AWACS, etc), so they spend a lot of time in a similar envelope to airliners.


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I’ve always heard about the dreaded ramp check. What does it actually entail?
What happens during a ramp check? How likely are you to experience one? What happens if they find something wrong? (A major and a minor example if you don’t mind)


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Is there a modern-day counterpart to the F-20 Tigershark?
A previous question (Would it be feasible to restart production of the F-20 Tigershark?) has established that restarting production of the F-20 Tigershark is not feasible. Given this, I wonder if there's a modern-day counterpart to the Tigershark. The F-20 was known for being cheap(ish, though the linked question demonstrates that it likely would not be today), reliable, easy to maintain, quick to scramble, and exceptionally maneuverable. Is there a modern-day aircraft that fills this role? I'm particularly interested in the low-cost, low-maintenance footprint, and rapid scramble attributes of the F-20. I'm not considering the F-16 to fill this role because it can launch within five minutes of the scramble order when on alert (15 minutes cold), and the F-20 could break ground within 60 seconds of the order.

Note that an aircraft’s role is based on the type of mission(s) it is designed to fulfill not on how cheap or easy it is to maintain.  It’s counterparts today would be the aircraft that are performing those missions regardless of how much they cost to acquire or maintain.

You're absolutely right. I'm more specifically curious about aircraft performing the same role that can still do it with lower maintenance costs and requirements. The aircraft's capabilities absolutely come first, but cost and required maintenance are important considerations for both less-wealthy nations as well as the distributed operations that would, without a doubt, occur in such a conflict in the Pacific as in the linked question.

Where do you get your information that the F20 could break ground within 60 seconds “of the order”?  (And what is the starting state before the order?) Because that's barely enough time to taxi at most airfields.

https://www.globalsecurity.org/military/systems/aircraft/f-20-specs.htm The starting state is assumed to be standing "strip alert". Regardless, the F-20 had the fastest scramble time of any jet in the world.

That link is nothing but pop-ups.  Without some actual definition of this state and direct comparison to other similar aircraft the distinction is nebulous at best.  What, specifically, does it take the F-16 5 minutes to accomplish that the F-20 can accomplish in 52 seconds?  I don't expect you to know, but you can't really have a meaningful discussion around the supposed superiority of one over the other without a deeper understanding.

I have been a turning spare for missions before.  Armed, manned, engines turning in the hold short, just waiting for the airborne package to call full mission capable before returning parking, or launching if needed.  From hearing the call to launch, releasing the parking brake, calling tower for takeoff, crossing the hold short, running up power and taking off I think you'd probably burn 52 seconds.  I faster lighter fighter might beat this by a few seconds, but if that's the state of the F-20 I can't imagine any tactical military jet being significantly any more or less capable of the same.

For instance the aircraft above. It is a Textron AirLand Scorpion, mentioned in this answer, which also quotes:

This is a composite fighter, designed with off-the-shelf parts, leaning heavily on technology developed for Cessna, who is the actual frame builder.

The wiki article expands on the target market and mentions the F-20 Tigershark:

The target market is the U.S. Air National Guard and foreign nations that cannot afford the F-35, but want an aircraft to perform ISR and light attack missions better than turboprop planes.[30] Buying and sustaining the Scorpion would cost less than A-10 or F-16 upgrades. For air patrol, the Scorpion requires radar and the capability of supersonic flight, similar to the unsuccessful 1980s-era Northrop F-20 Tigershark.

The article also mentions the F-16, the still formidable low-cost supersonic design of half a century ago, with much superior manoeuvring capabilities compared to the F-5/F-20. From the F-16 wiki:

The F-16 was designed to be relatively inexpensive to build and simpler to maintain than earlier-generation fighters. The airframe is built with about 80% aviation-grade aluminum alloys, 8% steel, 3% composites, and 1.5% titanium.


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For a PPL, do I pursue gliders or airplanes first?
I'm interested in pursuing a Private Pilot's License. I'm interested in both gliders and powered flight. Gliders look like fantastic fun and powered flight would be an amazing thing to have – I could take my family and friends for tons of day trips not otherwise possible. There are negatives to both – the glider club is an hour away, and powered aircraft are expensive. Does anyone have any insight on which would be better to do first?

It's a no brainer. From a pure skill perspective, if practical, do gliders first.  You will acquire perceptions and fine handling skills, and develop instincts and habits (speed control, energy management) to a higher level without the complication of the engine. You have to master the more sensitive and difficult to coordinate controls of a glider (not to mention "one chance to land", which helps take away some of the fear of engine failures when flying power).  Those habits will serve you extremely well when transitioning to power.
Also, gliding is flying for pure sport, as opposed to sightseeing or going places, and is more of an involved pastime. Clubs are group activities that depend on volunteer support, and it's a bit paradoxical really; you need to participate in the group, to do what is essentially a solitary activity (except when giving rides). So you have to be willing to commit full days to the activity, as opposed to going to the airport for a couple hours and going home.
Then there's the sport of soaring itself. It's like sailboats. You either are into it, the game you play with the atmosphere, or you aren't.  You need to find that out. If you are, it'll become a lifetime pastime.  Many power pilots learn to fly, go places for a while, then taper off as the novelty fades and the expenses increase, but for most glider pilots who are hard core about it, that is their thing all their lives, like sailing fanatics.

Thank you! That is a really good way of putting it.

Not quite sure if I entirely follow the logic in your last paragraph - of course the hardcore fanatics live and breathe gliding, that's true of any hobby including powered flight. And just like PPLers who drift away, many glider pilots do too. To me, they're related but fundamentally different hobbies - some will live and breathe one or the other, both, or none but I don't think there's anything inherent to either which makes it more or less likely. It's like comparing motorbiking and sports cars - if you love it, you love it, and that's about the sum of it IMHO


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How to find the remaining fuel without electrical power on the MD-80?
After a flight, how to find the remaining fuel without electrical power (even the APU) on the MD-80?

The normal Digital Fuel Quantity Display in the flight deck does not work without AC power, meaning you need to have either the APU running or external AC power connected:

Fuel Tank Quantity Indicating
A standardized modular fuel gauging system is used which requires no
  adjustment or calibration after system installation or component replacement.
The Digital Fuel Quantity Display is located on the center instrument panel
  to indicate the quantity of the three tanks and gross weight. Operation of this
  display requires normal AC power.

(MD-80 FCOM Sec. 13 - Fuel)
The Fuel Load Display Panel on the right wing however can be powered via the battery:

Fueling POWER Switch
OFF - Removes power from fuel load selector display panel and fuel fill valve switches.
ON - Supplies power from battery or external power to fuel load selector display panel and fuel fill valve switches.

(MD-80 FCOM Sec. 13 - Fuel - Controls and Indicators)
You can read off the current fuel levels in the upper row of the display panel:

(image source: MD-80 FCOM Sec. 13 - Fuel - Controls and Indicators)
Without battery power, manual measurements of fuel tank quantities are still possible with a magnastick:

Fueling and Defueling
[...]
All fueling operations can be accomplished with airplane or externally
  supplied electrical power. If electrical power is not available for fueling
  operations, all fuel tank valves can be manually operated and fuel quantity
  measured using magnasticks.

(MD-80 FCOM Sec. 13 - Fuel)
The following section from a Dash-8 manual describes how the magnastick (or magnetic dipstick) works:

(image source: Dash-8 Q400 FCOM)

Magnetic Dipstick Magnet
Float Magnet
Fuel Level in Main Tank
Calibrated Magnetic Dipstick

the magnetic dipsticks give an alternate means to measure the fuel quantity when the aircraft is on the ground
the magnetic dipstick is accessed at the bottom of the wing
when the rod is released, it moves slowly down until the rod magnet is attracted by the float magnet

(Dash-8 Q400 FCOM - Fuel)

Magnasticks
Two magnetic dipsticks (magna sticks) in each tank provide an alternate means of measuring fuel quantity when on the ground. Each consists of a calibrated rod, which slides within a tube extending vertically from the bottom of the fuel tank. When the rod is released, allow it to fall slowly until resistance is felt as the rod magnet becomes attracted to the float magnet. Read the tank contents from the bottom of the rod in U.S. gallons or in litres.

(Dash-8-200-300 FCOM - Fuel)

Very interesting. Can you explain the operation of the magnastick? It looks like you pull it down until the magnet at the top of the stick is "gripped" by the magnet in the float. The scale on the stick is decreasing numbers towards the top. To push the stick back in for flight I presume you have to use enough force to break the magnetic force - a sharp shove or thump?

@Transistor I found a nice explanation in the Dash-8 manuals and added it to the answer. It works exactly like you assumed.

On the MD80, the refueling valves are powered by the BAT DIR bus. The refueling panel is powered by the emergency inverter. So, the refueling load selector panel is always available to show fuel onboard as long as the battery is charged. (AMM 28-20-00 Fig. 10)

@SportsRacer You're right. I added it to the answer. Thanks for pointing that out ;)


text:
Is the waves and signal dangerous for human at the airports?
Waved like VHF , UHF and other themes like radio or something ....

Can you be more clear about your question?

I'm voting to close this question as off-topic because it is not about aviation but rather about biology and physics.

In favour of the question: airports are places of extraordinarily heavy em load with navaids, radios, radars and huge amounts of people using their personal comms...

Related: https://aviation.stackexchange.com/q/65274/23223

I feel like it's not on topic. The question here is "Are radio waves harmful to health, at the levels found at airports?" We may have some idea of the level of radio waves found at airports, but the other part of the question is totally off topic.

No. To people at the airport, the electromagnetic radiation from various sources relating to aviation (or anything else) is not dangerous.
Any electromagnetic radiation is, with enough intensity, possibly dangerous, even instantly lethal, but you can rest assured, that such intensities are not present anywhere a normal person has access to.

I disagree, weather radars are dangerous to ground crew and require specific procedures to mitigate said danger.

@AEheresupportsMonica hence "...anywhere a normal person has access to." I'm perfectly aware that some radars can fry your nuts if you manage to sneak close to one (I'm familiar with one case), but that's why access near them is limited.

thank you so much


text:
What Are these in the PFD?
I marked them with white circles. What are they for?

You are basically asking about the entire PFD (which seems to be from a 737NG). Have you tried googling/reading official docs from Boeing? you could have at least numbered the different items to make answering easier

Downvoters, please explain why you downvote. If you cannot find a way of improving this question, this will at least give clue to the OP for how to ask its next question.

I upvoted this question as it comes back to basics which is a good entry point for new comers.

@Mohammad Gohardoust - To further you’re interest in aviation, I would highly recommend becoming familiar with the standard steam gauge six-pack. Every airplane will have their own version of these instruments. If you add to that autopilot and VOR/ILS Course Deviation Indicators, you will be able to decipher most of the front panel of even the most sophisticated aircraft. Most of them have their PFDs set up in very similar fashions. A Garmin G1000 w/ GFC700 is a good example of a generic PFD for beginners.

thank you very much

.78:
This is the target speed or Mach number, meaning the aircraft should travel at $ 0.78 \times c $ (speed of sound). The current Mach number is 0.779 (shown in white at the bottom of the speed tape).

Selected Speed (magenta)
Displays target airspeed:

indicates the airspeed manually selected in the IAS/MACH window
indicates the FMC computed airspeed when the IAS/MACH window is
  blank.

ARM LNAV VNAV SPD:
This is the Flight Mode Annunciatior (FMA), indicating that the autothrottles are armed (ARM), the roll mode is Lateral Navigation (LNAV) and the pitch mode is vertical navigation speed (VNAV SPD).

1 Autothrottle (A/T) Engaged Mode
2 Roll Engaged Mode
4 Pitch Engaged Mode

Red band:
This is the so called Barber's pole indicating the indicated airspeed range that is above the current maximum speed.

Maximum Speed (red and black)
Bottom of the bar indicates the maximum speed as limited by the lowest of the
  following:

Vmo/Mmo
landing gear placard speed
flap placard speed.

CMD:
This is indicating that one of the autopilots is currently engaged in command mode (CMD). The 737 also has a different autopilot mode called control wheel steering (CWS).

7 Autopilot Status

(see previous image above)
254:
This is the current calibrated airspeed in knots. The magenta marker is the current target speed for the autothrottle / VNAV descent.

Current Airspeed (white)
Indicates current calibrated airspeed in knots.
  When current airspeed decreases into the minimum maneuver speed amber bar:

airspeed readout box turns amber and flashes for 10 seconds.
box returns to white when airspeed is above minimum maneuver speed.

Speed Bug (magenta)
Points to the airspeed:

manually selected in the IAS/MACH window
indicates the FMC computed airspeed when the IAS/MACH window is
  blank.

When the selected speed is off scale, the bug is parked at the top or bottom of the
  tape, with only one half bug visible.

36620:
This is the current altitude in feet as measured by the static ports. This is not necessarily the actual altitude above sea level because the reference pressure for the altimeter is set to STD (see below).

Current Altitude
Displays current altitude in increments of thousands, hundreds and twenty feet:

for positive values of altitude below 10,000 feet, a green crosshatch
  symbol is displayed
a negative sign appears when altitude below zero feet is displayed
readout box becomes bold to denote altitude acquisition
readout box is highlighted in amber and flashes to denote altitude
  deviation (refer to Chapter 4, Automatic Flight and Chapter 15, Warning
  Systems).

To the right of this (not circled in the picture, but worth mentioning) is a scale with a white needle pointing between numbers 2 and 6 on the scale:
This is the vertical speed indicator or VSI. It indicates the direction and rate of the planes vertical movement. The numbers on the scale indicate thousands of feet / second, and since the needle is pointing downwards, the plane is currently descending. Below the scale is numerical display giving the exact rate of descend or climb. In this case, the plane is  descending at 2800 feet/minute

REF 30/128:
This is the reference flaps and speed for landing. The pilots have already selected that they want to land with flaps 30 and at a reference speed of 128 knots in the CDU.

Speed Reference Display (green)
Displayed if the airspeed and/or weight is entered via the speed reference selector
  on the engine display control panel:

on the ground, V1, VR, and takeoff gross weight may be selected; if
  VREF is selected, INVALID ENTRY is displayed
in flight, VREF and landing gross weight may be selected; if V1 or VR is
  selected, INVALID ENTRY is displayed
removed when the speed reference selector is moved to the SET position.

STD 30.21 IN.:
This is the current and pre-selected altimeter reference pressure. STD means that the current reference pressure is 1013 hPa (29.92 inHg), which is the standard value selected above the transition altitude. The pilots have already pre-selected a value of 30.21 inHg, which will be activated when descending below (or being cleared below) the transition level.

Barometric Settings (green)
Indicates the barometric setting in either inches of mercury (IN) or hectopascals
  (HPA) as selected on the EFIS control panel.
  Display is boxed amber if numeric is set and airplane is climbing above transition
  altitude, or if STD is set and descending below transition flight level.
Preselected Barometric Setting (white)
STD is displayed when the Barometric Standard (STD) switch is selected on the
  EFIS control panel.
  When STD is displayed, a barometric setting can be preselected on the EFIS
  control panel barometric selector and is displayed in small white characters below
  STD.

Circle at bottom:
This is the current heading indicator. It is showing that the aircraft's nose is pointing towards 260 degrees as measured from magnetic North (see the green MAG text), but is actually moving across the ground (track) at 256 degrees (white line). The current selected heading on the MCP (mode control panel) is shown by the magenta marker and text (also 260 here).

1 Current Heading Pointer (white)
Indicates current heading.
2 Track Pointer (white)
Indicates current track.
3 Selected Heading (magenta)
Digital display of the selected heading bug.
4 Selected Heading Bug (magenta)
Indicates the heading selected on the mode control panel. If the selected heading
  exceeds the display range, the bug parks on the side of the compass rose in the
  direction of the shorter turn to the heading.
5 Magnetic/True Heading Annunciation (green)
Displays selected heading reference:

MAG indicates display is oriented relative to magnetic north
TRU indicates display is oriented relative to true north; a white box is
  displayed continuously around TRU

all images and quotes: Boeing 737 NG FCOMv2 (4.10 Automatic Flight - Controls and Indicators, 10.10 Flight Instruments, Displays - Controls and Indicators)

very useful Thank you very much

@Sami I always used $c$ for speed of sound, too. Wikipedia seems to do the same.

I took the liberty of adding a description of VSI even though it was not actually asked about...

thank you so much


text:
What is this in the primary flight Display?

What is this in the primary flight Display ?

From which aircraft type does it come from?

Chemtrail gauge.

It is a digital Angle of Attack Indicator. From the Boeing 737 FCOM:

Digital AOA Readout (white)
Indicates digital AOA value to the nearest 0.2 degrees. When on the ground and
  ground speed less than 80 knots, the readout is fixed at 0.0 degrees.
Stick Shaker Indicator (red)
Indicates point at which stick shaker activation occurs for existing flight
  conditions.
  Blank if AOA signal is invalid.
Analog Needle (white)
Indicates analog AOA value.

needle travel is limited to a range of -6 degrees and +21 degrees
fixed at 0.0 degrees when on the ground and ground speed is less than 80
  knots.

Approach Reference Band (green)
Indicates appropriate range of approach AOA for a Vref(xx) + 5 approach.

displayed when in normal or single engine landing flaps (15, 30, 40)
moves with flap position
inhibited on takeoff and initial climb.

Zero Degree Reference Line (white)
Indicates zero degrees angle of attack. Reference lines are displayed every 5
  degrees from -5 degrees to +20 degrees.

(Boeing 737 NG FCOMv2 10.11.11 Flight Instruments, Displays - PFD/ND - Displays)
All Boeing aircraft have at least two alpha vanes to measure angle of attack, but the cockpit display shown above is an airline option, i.e. not every aircraft will display this dial:

Angle–of–Attack
There are two alpha vanes, one located on each side of the forward fuselage. The
  vanes measure airplane angle–of–attack relative to the air mass.
[Option - Angle of attack indicator]
The primary source of data for the AOA indicator on the PFD is supplied by the
  ADIRU, with the Stall Management Yaw Damper (SMYD) as the backup source.
  The source selection is automatic in the event of primary source failure. Slight
  differences between the Captain’s and FO’s indications may be noticed due to
  sideslip or vane installation errors. These differences could be as large as 2
  degrees alpha.

Huh, I would have thought it a climb rate indicator.

@Davidw That is to the right of the altitude band ;)

That's the angle of attack display. The red marker is where the stall warning activates.


text:
How the German Horten Ho 229 flying wing can cancel the adverse yaw in turning?
How the German Horten Ho 229 flying wing type of aircraft-design, cancel the adverse yaw effect in oblique/  diagonally turns?How the pulley on the controls could mix up to do the dual role (bank and yaw inside the turn to cancel asymmetrical lift)?

The Ho229 does not have splitting ailerons.

Horten Ho 229 used "drag rudders" at the tips of the wing to control yaw:

Source
These devices are in the family of airbrakes, they create drag, not to be confused with spoilers which destruct lift.

I think we can be confident that those drag rudders did in fact cause some reduction of lift when deployed.   (Unless of course the wings had so much washout that that region of the wing actually created downward lift-- unlikely.)  Not to say that you are wrong about the primary purpose for which they were designed, but...


text:
Was the oxygen mask, on this flight, out of order?

Recently I was on flight where the panel for the oxygen mask, above my seat, looked like on the picture: the "button" in the middle of the panel was extended, turned and was showing a red tag on the side.
I asked a member of the cabin crew if this indicated a problem and the response - after he had tried to turn and push it in - was "I don't know, I don't think so". The fact that he couldn't turn it, or push it back into the panel, makes me think that it is more than just a locking mechanism, that it might have indicated that the system was out of order and I should've moved to a different seat.
Was my hunch correct, does this indicate a faulty oxygen mask?
The plane was an Embraer 190.

That panel looks too big to be one of the trap doors for the oxygen masks.

Looking at this video, https://www.youtube.com/watch?v=YMZQYJ9ASew, confirms that it is the door for the oxygen mask. Around the 1:10 mark you can even see the button that's extended on my picture.

According to this Airbus training manual, pages 10 and 11, that's the test door stop.
As you can see in the video you added, resetting the masks is a pain, so the little red stop is there to catch the door and stop it from fully opening.

Manually operated doors stops are fitted on the container doors to allow an operational test of the mask release system.
  When set to test position the door stops will prevent doors from fully opening and masks from dropping out of the Container.

Thanks, that solves the mystery :)
So basically the door for my oxygen mask was in test mode - a little concerning that the cabin crew did not know this!
This also answers my other question that, yes, I should've moved to another seat.

Here's some question regarding the ramifications of not putting on an oxygen mask: https://aviation.stackexchange.com/q/34159/567 https://aviation.stackexchange.com/q/2054/567


text:
What to do when circling restrictions conflict with VFR traffic pattern direction
At 4B8 (Robertson Field) there is a single published IAP: RNAV (GPS) 2.
For VFR traffic, the field is left traffic on both Rwy 2 and Rwy 20. However, there are large obstacles to the east of the field, so the RNAV procedure indicates “Circling NA east of Rwy 2-20. Circling Rwy 20 NA at night”. Certainly seems reasonable given the obstacles.
My question is: in practice is it possible to land here using Rwy 20 at all (during the day) without committing a violation while flying under IFR. I.e. if you follow the RNAV 2 approach, and you want to circle to land Rwy 20, the IAP requires you to circle west of the field (which would have you making right traffic). That doesn’t sound legal or fun for a field that is left traffic otherwise.
Of course you could break out high enough to cancel IFR and then make left traffic (to the east of the field but inside of the obstacles). But that clearly isn’t practical for a low IFR day. Is this field simply unusable for IFR traffic when the winds are from the south?

In this case there is no alternate runway (other than the reciprocal). So I guess the question is somewhat more pointed here. If right traffic to 20 is not allowed, then the only available IFR runway here is 2.


text:
What abbreviation for knots do pilots in non-English-speaking countries use?
In aviation, we abbreviate knots as kt. According to Wikipedia:

The ISO standard symbol for the knot is kn. The same symbol is preferred by the Institute of Electrical and Electronics Engineers (IEEE), while kt is also common, especially in aviation, where it is the form recommended by the International Civil Aviation Organization (ICAO).

The ICAO's recommendation is contained in Annex 5 to the Convention on International Civil Aviation, "Units of Measurement to be Used in Air and Ground Operations".
kt is an abbreviation of the English word. The kn ISO/IEEE standard version, when used in other languages, is customarily translated; for example, in French it's nd, short for "nœud".
How do pilots in non-English-speaking countries typically abbreviate knots? I can think of a couple possibilities – are any of these correct, or is it something else entirely?

Do they use kt (the English version) because English is the "default" language of international aviation?
Do they use a language-specific abbreviation with no difference for the aviation context, for example nd in French?
Do they use a language-specific abbreviation specific to the aviation context, similar to the distinction between kn and kt in English? If so, is there a list or resource explaining these, ideally for many languages?

Does the typical usage differ between languages/countries at all? What about between commercial and general aviation pilots? (For example, do French GA pilots use nd but commercial pilots more often use kt?)
Specific examples or evidence of the typical practice would be helpful.

Another point where context is everything. If it's clear that it's a speed, probably no one will interpret kt as kilo (metric) ton.

Where the instruments are marked in English, it's always option 1 - "kt". This holds for any country.
For non-English content, like translated or foreign-language manuals, it can be anything, "kt" or whatever that language uses, "nd", "уз", "節" or even "kn".
ISO "kn" is one of these things like megagrams and gigameters: technically correct, but impractical. Knots and kilometers can be used in the same context, making "kn" and "km" so easily confused as to be dangerous.

I don't think I've ever seen "nd" on an instrument, though. Ones old enough to still be in French are normally in km/h, France being the origin of the metric system, and new ones are of course "kt". The Swedish Viggen and most other older European aircraft also have their ASI marked in km/h. Russian instruments pre-1990 used metric, and newer ones in the SSJ and the MC-21 are all-English with "kt" as the abbreviation.
Thus it's option 4 for non-English cockpits: km/h or a local translation of the term. Switching from metric back to Imperial units only makes sense when you go for unification with English-based training and symbology, so you wouldn't translate anything.

Side note on origins; "France being the origin of the metric system" occurred in later 1790s. Interesting that just before that in 1792, USA went to metric/base-10 money with the mil, cent, dime,  dollar, etc.

I can't believe the French abandoned all reason and sanity just because everybody else did. That's so wrong! ;-)

ICAO recommendations
ICAO is the UN agency for international civil aviation. All State members apply its recommendations in their official aeronautical publications. Normally only SI units should be used, but there are only a few countries (Ex-Soviet block, China and perhaps India) which are actually compliant and use km/h for speed.
Other non-SI units are allowed by ICAO for specific measurements but they are supposed to be temporary. However there is no definite deadline; these non-SI units are therefore the de-facto and permanent standard for almost all countries.
ICAO recommends using knots (kt) for speed and wind speed in Annex 5 to the Chicago Convention:

Abbreviations are invariant, in the French version of the annex, the unit name is nœud, still abbreviated kt:

French official documentation
The French civil aviation agency publishes its French-language documentation with ICAO unit and abbreviation:

1.7.1 Lorsque des procédures sont conçues pour être utilisées en régions montagneuses, il faut tenir compte de l’erreur
altimétrique induite et des problèmes de contrôle que connaît le pilote lorsque des vents de 20 kt ou plus soufflent sur ces
régions. Lorsque ces conditions sont réputées exister, la MFO est majorée d’une valeur pouvant atteindre 100 %.

Source.
The French AIP use knots (noeuds in French, which should be spelled nœuds actually) and kt (sometimes they use a plural: kts, but this is an error):

Tout aéronef à voilure fixe ayant une masse maximale certifiée au décollage supérieure à 5 700 kg ou ayant une capacité maximale de vitesse vraie au niveau de vol de croisière supérieure à 250 nœuds [..]

Unit/abbreviation used by country

is there a list or resource explaining these, ideally for many languages?

The AIP is the official aeronautical documentation for a country. It states which units are used in the country, at section GEN 2.1. E.g. in France:

Unfortunately I've no consolidated list.
Flight education
Flying schools use kt as expected (but I've seen many non standard spellings in GA course material):

Noter qu’une vitesse d’approche finale supérieure de 10 kt à la normale, entraîne une augmentation de la distance d’atterrissage d’environ 100 m.

Manufacturers
Manufacturers are also supposed to use the same speed unit and abbreviation, however there are a few speed indicators using km/h in some cockpits (like there are a few indicators in statute miles in the English world). It's an exception which can be ignored.
Pilots
Official publications must use the standard proposed by ICAO, and pilots, for GA or airliners, with a private or professional license, are not supposed to use anything else for obvious reasons.

Is km/h even an SI unit? Shouldn't it be m/s?

@Michael, km/h is accepted when using the SI (km is a multiple of a SI unit and hour is a non-SI unit accepted for use with the SI units, source).

Specific examples or evidence of the typical practice would be helpful.

The Dutch weather forecast for general aviation (Weerbulletin voor de luchtvaart), issued by the KNMI (Royal Netherlands Meteorological Institute) uses Dutch abbreviations for all units. For wind, this means "kn", short for "knopen"="knots". For altitude, the abbreviation "vt" for "voet"="feet" is used.


text:
Are jet engines designed in a way to make an explosion result in the least damage possible?
I know most engines are super reliable today, but do manufacturers do anything to at least make an explosion result in the least damage possible?

Fun fact:  If you're riding in a Dash 8, look for the little vertical red stripe on the inside of the nacelles.  That's where the turbine disc is.

Southwest Flight #1380, April 2018, had the left engine explode with shrapnel piercing the cabin and damaging control surfaces on the wing. The pilot was still able to successfully land. There are a few dramatization, and scientific discussion, videos of this event on youtube.

The most (kinetic) energy is in the fan and turbine blades and disc. The engine is enclosed in a containment chamber whose purpose it is to protect the rest of the airplane from shrapnel in case of a fan disc or fan blade failure. Here's a video of a test where a fan blade failure is simulated:

 As you can see, the fan blade more or less completely destroys the engine, but no debris or shrapnel leaves the containment chamber.
Unfortunately, the turbine disc and blades have too much energy to be realistically containable. (In other words: the required shielding would be too thick and heavy.)
Engine failures where debris or shrapnel is able to leave the containment chamber is called an uncontained engine failure, and they are very rare, but they still do happen.
Since it is impossible to contain a turbine blade or disc failure, risks are mitigated in different ways, e.g. by requiring regular, very detailed inspections and extremely tight tolerances.

I disagree with your first statement. I was of the understanding that the turbine discs/blades had the most energy and were uncontainable.

Blade and vane failures are bad, but a disc failure is about certain to be catastrophic.

Indeed, the reason why the failure on QF32 was uncontained was because it threw a turbine disc. Pieces of the disc punctured the wing, severing multiple electronic and hydraulic lines, as well as blowing holes in the wing fuel tanks. It was the #2 engine (inboard left side) that failed, but, due to the severed control lines, the #1 engine (left outboard) was also rendered uncontrollable. Even after they landed, they ultimately had to foam the #1 engine in order to shut it down. They weren't even able to cut off fuel flow to it.

In 2018, there were a couple incidents where a poorly maintained turbine had fan blades shear off in just the wrong location, hitting a structural weakness and causing explosive decompression in the cabin from engine shrapnel hitting a window. One of the planes had someone almost sucked out of the plane, and even though the pilots did an outstanding job landing the plane quickly and safely, the affected passenger did end up dying.

That's still "designed to do the least damage possible", a.k.a. design-basis event. That mother nature can come up with scenarios that go beyond the design basis is the reason why life can become so interesting all of a sudden...

The main place engine manufacturers will focus on minimizing damage is with the large fan at the front of a turbofan engine. FAA Advisory Circular 33-5 discusses the regulations that cover this. The manufacturer must show that the worst case blade rotating at the highest RPM can successfully be contained. Only 15 seconds after the event is the operator allowed to adjust engine controls. The engine and related structure must also be able to withstand the resulting imbalance for the rest of the flight, especially for ETOPS certification. While the windmilling engine will produce drag, the aircraft will still remain controllable.
However, an engine failure is an extremely dynamic event, dissipating large amounts of energy. It's up to the aircraft manufacturer to ensure the engines do not pose a threat to safety of flight in the event of an uncontained engine failure. FAA Advisory Circular 20-128A discusses some of the methods on minimizing the hazards of an uncontained engine failure on the airplane. Below is a figure from this document showing typical locations of systems in the fuselage.

Each critical system will have redundancy, and is routed such that debris from an engine failure cannot damage enough systems to prevent safety of flight. Below, tail mounted engine is shown, plotting debris paths versus systems locations.

The FAA also published a report on Large Engine Uncontained Debris Analysis. This report is full of statistics and photos of damage caused by uncontained engine failures. Analysis considers the size of the debris involved, the speed at which it impacts other structure, and relative angles between the debris and impact surface.

One of the most critical systems to protect in a twin-engine airplane is the remaining engine. Shielding may be required to prevent debris from one engine from crossing over and damaging critical parts of the other engine. Manufacturers have also sought patents on ways of tilting the engines to keep them out of each other's debris paths.
New technologies such as open rotor fans present additional challenges to protect the aircraft from a blade failure, as there is no fan case to contain them.

A jet engine may not contain a severe explosion (for whatever reason) but there are various mandated things that are put in place to help protect the airframe.

The engines are generally mounted such that they shear off cleanly and away from the airframe.
There are a few AC's like this one and this one that discuss how to deal with and comply with various safety regulations around unconfined blade failure and unconfined rotor failure, as well as this one about pylon loading.
Jets are generally produced to a very high standard to prevent issues from happening in the first place which is in a way a safety consideration.

Cowlings can be designed to contain fan failures but if the core comes apart you have some pretty high velocity shrapnel coming out that nothing short of quarter inch armour plate will stop.
The main design feature you typically see to mitigate burst risk is the placement of cable runs and hydraulic runs, where there are redundant runs, spaced apart in the fuselage to reduce this risk of shrapnel taking out all of the cable runs from a burst (as happened with that DC-10 all those years ago, because they were forced to run right next to the tail engine to get to the fin).  You might also see strategically placed armour plates located between a cable run and the turbine disc, where a single run is critical for safety.
Beyond that, control of risk is mostly about maintenance and inspection of the components, same as with things like primary structure.  When turbine bursts happen it's usually because of some microscopic manufacturing flaw in the disc that went undetected and falls into the random s--t happens category.  As I like to say, it's a dangerous world for everybody but rocks.

So let me guess... quarter inch armor plate is a tad heavy, so you don't use that?

Would quarter-inch plating even stop pieces of a turbine disc at high RPM? In QF32, they blew straight through the wing entire wing. Luckily, none of them struck the fuselage. High-velocity pieces of jet engines flying into the passenger cabin are typically fatal.

...did you mean quarter-inch or quarter-foot?

Wasn't meant to be literal. However, the standard NATO 1/4" hardened steel armour plate will stop 7.62mm so it should stop a chunk of turbine disc or blade after having been slowed by the engine case and fuselage, and the unlucky seated individual who gets in its way.

@JohnK A typical turbine rotor stage has a mass of around 100kg. A catastrophic failure will usually produce one "fragment" with about half the total mass. Stopping a 7.62mm bullet is an irrelevant comparison.

I once saw some pictures of a C130 aircraft which had a propeller blade fail and detach - lucklly, while on the ground, and the aircraft was empty. There was a neat blade-shaped hole in the over-wing exit door where the blade entered the aircraft, and a similar hole in the opposite door where it exited. So much for "containment of explosions" in real life.

Yes you'll get a couple of large chunks and all kinds of smaller ones.  I'm talking about the smaller ones.

@JohnK Why are you talking about the smaller ones?  It's the big ones that do the damage.  If you can mitigate the damage they do, it will cope with the small stuff too.

@MartinBonnersupportsMonica the "hit probability" is much higher for the many small chunks. If a half-disc heads for the fuselage, you're done anyway.


text:
Does airspeed come into play with vertical speed, in terms of who will reach the ground first?
So let’s say there’s two aircraft, which are the same, and both are cruising at 28,000FT, the only difference is one plane is doing 260 knots and the other is doing 280 knots. If they both pitched down reaching a vertical speed of -15,000FT/Min at the same exact time, would the aircraft going 280 knots still hit the ground first despite sharing a vertical speed the entire time??

The question is too vague. As asked, it seems like a straightforward physics problem, and a trivial one at that (since you've declared that the vertical movement is identical for both aircraft), nothing really to do with aviation. On the other hand you haven't defined "ground". If the "ground" is actually a mountain some distance ahead, the horizontal speed will matter more than vertical, because that defines how soon the aircraft will reach that ground.

No, both would reach the ground at the same time, although the one with the higher airspeed would go farther before hitting the ground, assuming atmospheric conditions are invariant.
On the other hand, if both aircraft have the same flight path angle, the one with the higher airspeed would have a higher sink rate.

Didn't do the math, but 15,000 feet/min is nearly a vertical descent.

@Ron Beyer Do the math.  $a^2 + b^2 = c^2$.  Descent angle is closer to 45 degrees.

@RobertDiGiovanni I'm not sure how you can apply that formula, it's descent rate, not distance. From 28,000 feet at 15,000 feet/min it takes 2 minutes. The descent angle is actually 88 degrees.

@RonByer The steepest would be near SL with 260KCAS=440ft/s. 15000fpm = 250ft/s. So that gives a descent angle of -30deg. At 28000ft, it's more like -25deg. Still extremely steep indeed.

@Ron Bayer covert the airspeed to miles per minute (4.5 ish) and the descent rate is around 3 miles per minute.  The airspeed is the hypotenuse.  Also there is feet per knot conversion.  And yes, TAS!  Thanks JZYL!


text:
What stops a pilot from flying VFR and going IFR?
Even if the pilot is instrument rated, what stops them from doing it anyway? I’d imagine in certain situations where danger is approaching, it may be best to switch to IFR, it can’t be that hard to rely on your instruments to get through a cloud? Would controllers know if you switched from VFR to IFR and this could get you in trouble or something?

@DaveGremlin but what makes it so difficult? Just look at your instruments, gotta be a lot better of an idea than looking outside when it’s completely foggy..?

Read the answers to this question:  https://aviation.stackexchange.com/questions/31198/why-does-flying-ifr-require-a-rating

What stops them? Hopefully common sense. An immunity to getthereitis. Fear of being turned into a lump of ground beef. The spouse. That little voice in the head that sounds like your first CFI talking to you about old, bold pilots. That kind of thing.

I think you need to clarify the question a bit.  Do you mean a non-instrument rated pilot flying into instrument conditions (basically suicide), or an instrument-rated pilot going from VFR into instrument conditions without bothering to file an IFR flight plan?  Which someone might do fairly safely if there's no other traffic in the area.

"Even if the pilot is instrument rated, what stops them from doing it anyway?" – Did you mean to write "even if the pilot is not instrument rated"?

@TomMcW - My mistake, comments deleted

You are confusing VFR, VMC, IFR and IMC.  Let’s briefly define the terms before I attempt to answer your question:
VFR – Visual Flight Rules.  The pilot navigates at will, but must comply with cloud clearance and airspace requirements.
VMC – Visual Meteorological Conditions.  The weather is good enough to operate under VFR.
IFR – Instrument Flight Rules.  The pilot must file a flight plan with ATC and be cleared for the altitude and route flown.  This defined and regulated process is required under IMC, but can also be followed when the weather is clear.
IMC – Instrument Meteorological Conditions.  Weather conditions are poor enough that operation under IFR is required.
So to answer your question, if an instrument rated pilot is operating under VFR and finds him or herself unable to maintain VFR cloud clearance requirements, (i.e. the weather is no longer VMC) then they should contact ATC immediately and request an IFR clearance.  By definition it is not possible to fly under IFR without the knowledge and consent of ATC.
And yes, it is possible to fly into IMC without ATC's knowledge or a clearance, but it is neither safe nor legal.  It is unsafe for the non-instrument rated pilot because of the extreme likelihood of spacial disorientation, and for both because of the risk of loss of separation from other traffic.  An instrument rated pilot would of course be able to rely on their skills to penetrate a cloud safely, but it is not something that can be done at pilot's discretion as you suggest.
I am guessing that the origin of your question is what we call “inadvertent IMC”.  In this case, instrument rated or not, the pilot should fly by reference to their instruments and execute a level 180 degree turn to exit the cloud.  This is an emergency situation.

"…it is not possible to fly under IFR without the knowledge and consent of ATC." True in controlled airspace, not true in uncontrolled airspace (that is, Class G airspace). You might still be violating FAR 91.13 (careless and reckless), though, if you're in G in IMC just cruising around and "something bad" happens.

How would you be operating on an IFR clearance without the knowledge and consent of ATC?  Anywhere?  Or are you confusing IFR and IMC?

P.S.  When I was instructing I would hear students occasionally use the term "inadvertent IFR".  When they did, I would ask them how they might accidentally pick up a clearance limit, route, altitude, and squawk.  But I did it with a friendly twinkle in my eye to emphasize that it was a learning point!  ;)

@MichaelHall You can't get an ATC clearance in uncontrolled airspace; that's literally what the term means. This isn't obvious in CONUS, which has very little class G, but notice the phrasing "upon entering controlled airspace" when departing class G airports: your IFR clearance does not actually begin until you get to (at least) class E.

@StephenS, is there something in what I have said that leads you to believe that I don't understand that?  I am agreeing with you!  ammPilot directly inferred above that you could operate under an instrument flight rules clearance in class G without ATC even knowing that you were cleared.  I refute that, but rather than simply declare him wrong I did it in a questioning way to challenge him to examine his rationale for saying what he said.

@MichaelHall You said "By definition it is not possible to fly under IFR without the knowledge and consent of ATC." That is only correct in controlled airspace. ATC can't grant you an IFR clearance in uncontrolled airspace, and there is no requirement to even notify them.

@StephenS - I agree that ATC cannot grant an IFR clearance in uncontrolled airspace. That being true, how could you fly IFR in uncontrolled airspace?  Because "by definition", in order to be operating under IFR you must have a clearance.  (please re-read my definitions of IFR and IMC above before answering if necessary...)

@MichaelHall That's probably worth its own question.

@StephenS - Then ask it.  I am perfectly clear on the answer.  You are contradicting yourself by claiming that my quoted statement is untrue for uncontrolled airspace, yet also claiming that ATC can't grant a clearance in uncontrolled airspace.  I think you are probably confusing IFR with IMC, but you haven't provided enough logic behind your responses for me to challenge that or correct you.  Please clarify your position, or stop arguing with me.

Let us continue this discussion in chat.

“execute a level 180 degree turn to exit the cloud” and oh oh there’s a mountain in that cloud :-(

@jcaron, if you are uncomfortable with that you can always do an immelmann.  ;)

Without going into the definitions of IFR, VFR, IMC, VMC, which has been so well covered...
Pilots CAN and DO fly VFR into IMC all the time. The NTSB actually has statistics on this occurrence. They usually are alerted to it by the big crashy noise the plane makes.
The reason responsible pilots can and don’t fly VFR into IMC is that it is neither safe nor legal. Just like your car CAN probably go over 120 miles an hour (200kph), a responsible person doesn’t. Even if you can do it without crashing into someone or something, it is still not legal (in most places). You may get away with it because the police can not cover the entire road system with radar. But, it is still not safe.
Flying VFR, you have to stay a certain distance from clouds depending on where you are. You also have to have a certain amount of visibility. ATC can not see the clouds nor visibility on radar. They can only see precipitation. They do know what the ground based weather stations say the sky coverage and visibility is in that area. At a certain level, they will call that entire area IMC.
You could try flying in clouds in an area designated VMC. If you pop out of the clouds and nearly hit someone, that other pilot has to report the incident. Or, ATC will also file a report of a near miss recorded on their radar regardless of clouds and visibility. The two reports will eventually meet each other.
Even if you don’t have a near mid-air collision, other pilots can report you based on the fact that they see you popping out of the clouds. But, they don’t hear you in communication with ATC on the radio.
In any of the above mentioned incidents you could face legal repercussions. ATC radar coverage is way more complete than police radar coverage. Even if you are squawking VFR, or not squawking at all, they can track you down by reviewing the radar records of where and when you took off and landed.
The IFR/VFR rules are written in blood for a reason. Yesterday it was too foggy to fly. A pilot decided to taxi their plane back to the hangar. Since they were not on the movement area (taxiway nor runway), I doubt they got ATC Ground clearance. I could hear their engine from the apron/ramp about 1000 feet away. But, I could not see them. Now, imagine if I had been in my cockpit with my headphones on and my just as loud engine running. How about if we had both been moving. Imagine the catastrophe that would have happened at 10-20 mph. In the air, we would have slim chance of survival.

Visual Flight Rules (VFR) and Instrument Flight Rules (IFR) are, as the names imply, two sets of rules that govern how a pilot flies. Assuming you are in controlled airspace, ATC will know which rules you are using, and if you want/need to switch, you must coordinate with them because it affects the services they provide (or don't provide) to you and possibly other aircraft around you.
One of the key differences is that VFR aircraft are expected to be able to "see and avoid" other aircraft, terrain, obstacles, etc., and the rules require a certain minimum visibility, distance from clouds, etc. so that they can reliably do so. In most airspace, VFR aircraft aren't required to be talking to ATC, and even if they are, ATC will still assume they are following the rules and thus don't need help not hitting things.
What this means is that if a VFR aircraft flies into a cloud, that breaks the most fundamental assumption of VFR flight, which can put the aircraft in grave danger from collision with other aircraft, terrain, obstacles, etc. That's why it's illegal.
Spatial disorientation is just icing on the cake.


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Why were the windows on the Concorde about the size of a hand?
I just saw a comparison between the 787 and Concorde windows. I could be wrong but it almost seems like a hand could cover the majority of the window.

Very related: What are the factors behind increasing aircraft window sizes

The guy on the right has bigger hands.

IMO, this is a direct duplicate of the Question @PeterKämpf posted

@Jamiec I didn’t take anyone’s question

@Firefighter1 no, you misunderstand. I don't mean you copied the question, I mean we already have a very similar question that answers yours. It's called a duplicate.

@Jamiec: Now that we have some proof that window size was part of the cabin pressure loss strategy, I think this question has merit on its own.

The Concorde flew above 15,000m. At this altitude a sudden reduction in cabin pressure would prove hazardous to crew and passengers with most falling unconscious within a few seconds. The low air-pressure would also render the oxygen supply system inefficient and most passengers would suffer from hypoxia.
Thus we have the reason for the smaller windows, should a breach occur then the size of the hole being small would reduce the rate if loss of air-pressure inside the cabin. This, combined with a reserve air-supply to augment the cabin-pressure as well as a rapid rate of descent manoeuvre to bring the aircraft to a safe altitude would reduce the the risk of hypoxia.
So basically the small windows were designed to reduce the rate of air escape from the cabin should a hull breach occur.

Nice first answer! Do you have a source for this?

I very much doubt that a descent to 4000 m from 15000 m within the time it takes to suffocate would had been possible.

Please provide a reference.

some reference from airliners.net

Edited to add link with the information that I expect is the source of the post.

@PeterKämpf in a rapid decompression at 55000 ft a fit person might last 15 sec, but a smoker, probably 1/3 to 1/2 of passengers at the time, would be out cold in about 5-10 seconds.   Even if masks dropped, probably a third of the pax, those that failed to don masks immediately, would be unconscious before they got past 40000 ft.  The little windows and secondary method to dump extra air into the cabin (I'm guessing an emergency bleed source) seems to be intended to buy a bit of extra time to give pax a chance to don masks.

@JohnK: Thank you for the explanation, the window size was indeed part of the emergency procedure. I still wonder how much of that was wishful thinking and how much was proven procedure.

Well at 40000 feet you might have 30-45 seconds to get your mask on, so they must've calculated they could slow the depressurization just enough to buy that little bit of extra time.  Now I'm curious to find out how this supplemental air system worked.

@John K In the comment above by Rsf is a link to an airliners.net discussion. There it is mentioned, that the size of the window of a Concorde is about the same as the cabin outflow valve. So if a window  was lost, one of the two outflow valves would close, and all would be relatively ok. This is, of course, info extracted from an internet discussion, and as such, should be taken with a grain of salt.

It gets worse. Oxygen at ambient pressure is only good up to about 41,000 ft. Above that you need a mask with overpressure to stay conscious. That's why there are additional requirements for flying higher (IIRC simply showing that probability of cabin altitude exceeding 41,000 ft is less than 10¯⁹ per flight hour). I am sure there is a detailed explanation somewhere around this site, but I am not sure I'll be able to find it given the general state of the search.

… I found mention here, and it actually says occupants must not be exposed to more than 40,000 ft, not 41,000 ft.

… I also can't find any decent reference (not just here, but anywhere) for the actual altitude above which ambient pressure pure oxygen is not enough for most people, but I am quite sure it is the reason behind that “must not be exposed to cabin altitude above 40,000 ft” rule.

@Jpe61 at altitude the outflow valves will be partially closed anyway, depending on how leaky the cabin is (door seals mostly, although I would have expected Concorde's leakage to be way less than the average airliner) and I would expect the outlet area at any given time would be less than with the valve fully open. But in any case, when the outflow valves close the rest of the way and supplemental air starts, it would be interesting to see what cabin altitude could be maintained with air dumping out a window.

Losing consciousness and death are not the same thing. The plane might have time to descent to a decent altitude before people decease.

Smokers have actually done better in thin atmosphere according to my experience. A two-pack-a-day friend of mine was solving logic and math problems while the rest of us were struggling to stay awake.  They eventually just had to move on with the excercise because he wasn't being effected.

Would the smaller windows really have significantly decreased the risk to Concorde passengers from a decompression, though?  Don't the vast majority of decompressions result either from localised (one hopes!) ruptures in the fuselage skin resulting from accumulated fatigue damage, or from externally-caused damage to the pressure hull (either penetrating it directly [for instance, engine rotor burst] or weakening it to the point where it ruptures under normal flight/pressurisation loads [for instance, errant ground vehicles], and, in either case, again usually involving the fuselage skin)?

@acpilot: Makes sense; smoking decreases the efficiency of oxygen transport, but also forces the body to adapt to a lower effective oxygen concentration.  A smoker who's not smoking at that moment would have the beneficial effects of adaptation to (slight) hypoxia, without actually having to deal with the smoking-induced hypoxia (somewhat like athletes training at high altitudes).

The fuselage is a pressure tank, the window is a hole in the construction of the pressure tank. Adding windows also adds weight: the pressure vessel construction must be reinforced around the hole. The window glass is obviously airtight, but does not contribute in absorbing any of the stresses of the pressure differential.
The window size is a function of:

The pressure differential. The higher the aeroplane flies, the larger the pressure differential between internal and external pressure.
The relative size of the hole, relative to the fuselage diameter, fuselage length, and aerodynamic bending forces.

For construction engineers, the best size of a window is zero. The windows in Concorde must be smaller because the fuselage diameter is much less than that of a B787 while it must handle a higher pressure differential.

Airflow Rate through an Orifice will help give some idea of the time it takes for the cabin of the Concorde to evacuate after one window blows at 60,000 feet as follows:
Volume of the cabin: $50m × pi × 2m^2 = 620 m^3$,
Diameter of orifice:  $0.15 m$
Rate of outflow from calculator software, averaged for pressure difference from T0 to T fully evacuated: around $150 m^3/min$ yielding roughly 180 to 240 seconds to full evacuation, without pressure equalization (reserve air-supply), with debilitating unmasked hypoxia sooner.
The location of the orifice (open window), on the side of the fuselage, could possibly cause even lower evacuation time values due to the Bernoulli effect of the passing airstream.
This underscores the point of view that strengthening the windows was indeed of critical importance.  Further examination of air replenishment capacity and emergency descent capability are in order, as newer versions of these supersonic transports may yet return to commercial use.


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Why does the stick force per-g test require it to be harder for pilots to pull back on the yoke instead of easier?
What happens when it’s easier to pull back banked at such steep angles, wouldn’t it be a good thing that a pilot can maintain his altitude easier than harde?

What happens when the pilot greys out and his hand moves? Should it return to center or be easy to fully deflect?

No because if stick force per G is too low, when maneuvering it becomes too easy to pull a lot of G and that's bad. It's like having power brakes in your car that don't build up more resistance in the pedal the harder you brake; it becomes difficult to regulate braking effort and too easy to lock the brakes (assuming no ABS).   Like with brakes, it's desirable to have the stick force build smoothly  with G force, because this provides good tactile feed back that helps you regulate how hard to pull.
If the force gradient is too shallow, too little effort is required to pull G and if above maneuvering speed it becomes too easy to pull the wings off by yanking on the stick too hard, and if below maneuvering speed, too easy to enter an accelerated stall while maneuvering.
It's an interesting point you brought up because there is a very popular 2-place cabin homebuilt airplane called the Wittman Tailwind, that's been around since the 50s. A very speedy, efficient airplane, designed by a famous air racer.  It has a very shallow stick force gradient, which builds to only about 5 lbs at limit load (I'm recalling from an article from the 80s).  This means if you are above maneuvering speed, it only takes a 6 or 7 pound pull on the stick to possibly pull the wings off, or at minimum bend something.  Wittman designed in the shallow force gradient on purpose because he was a pylon racer and really liked very light controls including pitch, more or less for similar reasons as you described.
However the Tailwind is not for the ham-fisted.  A pilot that is used to the airplane and had a light touch would be fine with it and would enjoy the very low stick forces, but for someone not adapted to it, it's dangerous.  Most airplanes have stick forces that build to 20-40 pounds or more, but you are never pulling that force in anything but aerobatic maneuvers.  Most normal maneuvering requires a 5 or 10 pound pull, and you're only holding it for a short time.
Transport airplanes with hydraulic controls get their stick force gradients by artificial feel devices that mimic the feedback forces that you would feel from airloads if the controls were manual, with loads that increase with speed and G.  I dimly recall that on the CRJ airliners the feel force for pitch was limited to 50 lbs and I believe most transport airplanes are similar.

Isn't thair zero force per G in Airbus aircraft?

There is a force feedback in the joystick configured around forearm and wrist muscles and you still have to pull a little harder the more G you pull, but you also have the computers to take care of the extremes preventing you from stalling or overstressing.

As mentioned in this answer: stick forces are designed into the control feel. The best feedback for the pilots on how large their control input is, is haptic feedback: push/pull force as detected by the force transducers in our hands. While looking out of a cockpit window, we don't exactly know where our hands are, but we don't have to look at our hands to instinctively know how hard we are pulling on a stick.
A banked turn causes increased g-forces on the airframe. It should be progressively more difficult to introduce more stress, and there is no better way to do this than via a force increase to reach a higher g level. If twice the g-stress level can be reached via an easy pull on the stick, it becomes too easy to reach an overload situation.

authors: Vladimir F Героям слава


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How can a runaway trim become so difficult to fight when all a pilot has to do, is “grasp and hold?”
and how can you even tell the pilots did “grasp and hold” during an investigation? Is it determined based off what they say?

What are you referring to specifically?

The force can quickly become stronger than any human can pull.  The recent 737-Max accidents were not a case of runaway trim; it was intermittent incorrect trim, which is quite different.

Grasp and hold is one thing. But if it ends up too far in one direction, it has to be manually cranked back against the aero forces.

@abelenky: Not just that, it can easily become stronger than the maximum opposing force the primary flight controls are physically capable of providing.

As I remember, runaway trim scenarios in the 727 sim produced control forces that a physically small pilot would have trouble maintaining, especially if combined with a jammed stab, the combination of which was often used in sim training.

@firefighter1 when you say "grasp and hold" it implies the manual trim wheel. Its designed not to be hard to hold, but if it goes too far (nose down), it takes time to manually crank it back. In cases of runaway trim, the electric trim control is usually turned off, so it because a manual exercise.

The FDR would show exactly what the control inputs were so they would know from that.
It's important to understand that pitch trim effectively controls the airspeed the airplane will seek naturally without any control input (FAR 25 pitch stability requirements specifically require airplanes to effectively seek a trimmed speed within certain parameters when the airplane is sped up or slowed from trim speed and left on its own).
If trim speed is higher than the actual speed, the airplane will pitch down (trying to accelerate to its trim speed) and vise versa if trim speed is lower than actual.  If you are trimmed at 180kt, the airplane will do whatever it has to do to maintain 180kt by going up or down hill (set aside thrust for now).  If you move the trim nose down, you are effectively telling the airplane to seek a higher speed, and it will oblige by pitching down until it's at its new trim speed and then stop changing in pitch.
If you are trimmed out at 180 kt and the trim "runs away" in the nose down direction, what's happening is your trim speed is increasing, and if you disable the trim to stop the runaway, you are now stuck with the new trim speed set by the position of the now disabled trim system.
If it runs away nose down and you kill it a couple seconds later, you had an airplane that wanted to seek 180kt "hands off" now wanting to seek some higher speed, say 250kt.  To keep 180kt, you have to apply a continuous elevator input, basically counteracting the stabilizer.  You will have a stab that is set more leading edge up than it was, while you hold the elevator more trailing edge up (you have to hold it displaced from neutral relative to the stab surface) to keep flying at 180 kt, and if you let go, the airplane will do what it wants to do, which is seek 250kt (in this example), and it will pitch over and accelerate.
So when you have a Nose Down stab runaway and you disabled the system, you are now stuck having to hold up elevator input continuously to fly any slower than the speed set by the stab's new position.  This can be up to 50lbs depending on how far apart the trim speed and the speed you want to fly at is (on a jet with hydraulic controls there is no aerodynamic feedback and you are just pulling against an artificial feel system, typically springs of some kind).
So there you are, "grasping and holding" the elevator to keep the airplane from pitching over to seek the new much higher trim speed that was set by the stab moving unexpectedly nose down until you killed its motion.  It might be, say, 30 lbs.  Your arms get pretty tired and you have to take turns.
Therein lies the temptation to maybe try to cheat the stab back to a lower trim speed by reengaging it, even though it violates your procedures.  In the case of the 737, you have manual trim capability, but it gets really difficult to move due to the load on the screw jack if actual speed and trim speed are far apart so it may not really be available (you actually have to let the airplane go and pitch over and maybe even help it along with elevator to offload the screw jack so you can move it - not feasible when close to the ground).
Stab trim runaway scenarios are done in the sim during training and recurrent, but that's normally a simple runaway, clacker goes off, disconnect, and deal with the situation from there.  In the MAX case it wasn't a typically simulator training runaway situation; the MCAS system was doing its weird timed trim pulse thing when it shouldn't have been, and the crew didn't even know the system existed, so they're doing their stuff with a strong "what the hell is going on?" factor added, with an airplane originally trimmed for climb speed now wanting to go a lot faster unless elevator is held, sowing the seeds of confusion and increasing the risk of brain-lock (I've experienced brain-lock in the simulator), which seems to be what resulted in these cases.

The phrase "grasp and hold" refers to the stab trim wheel itself, in the 737 checklist, which is likely what prompted this question. The fist step is "Control Column - hold firmly", then a/p & a/t off, then cutout switches, and only then (if the runaway continues even with the cutout switches in "cutout") stab trim wheel - grasp & hold. Which DOES stop the runaway just fine, but is unnecessary unless the cutout switches were to fail closed.  Which hasn't happened in any event I'm aware of.

Double failures within a system are generally not accounted for in system design anyway, from a risk perspective.  I dunno how you are expected to grab, stop and hold a trim wheel is is spinning at the high speed it spins at during the MCAS pulses anyway.  What a bizarre procedure.

You don't have to. The switches cut it out entirely. "Grasping and holding" the spinning trim wheel is there for the hypothetical case that the switches fail, but the reality is that the cutout switches work fine.  Worked fine for the crew-of-3 in the Lion Air flight prior to the accident (when they were used), and worked fine in the Ethiopian crash too (until they were turned back on).  The focus on "grasp and hold" is a distraction. If the trim isn't doing right, turn the switches off. Easy. Maintain control of your airspeed, trim manually, return & land. Shouldn't be hard.

I realize that, but it sounds like somebody got carried away with the what-ifs when developing the QRH procedure lol.  I've been a (very minor) participant/observer in development of QRH related procedures and have seen that sort of thing result in order to mollify certain stake holders.


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What makes airplanes pitch up during landing?
So what exactly pitches the plane upward with the rear end down? Do flaps help lower the nose when deployed 80%-100% down with such low speeds?

The elevator is used to pitch up the aircraft just prior to touch down. That is a flap at the rear at the airplane that deflects upwards and thus pushes the tail down and the nose up.

It's not real clear whether you are asking about pitch torque generated by flaps, or about how flap deployment affects the angle-of-attack that correlates to a given airspeed, or about how the pilot controls the pitch attitude and executes the landing flare.  Looks like various answers have addressed various ones of these; probably too late to edit now as you may invalidate an existing answer.

The change in pitch during the landing is called the flare and it is controlled by the pilot (or autopilot for an autoland) using the elevators (i.e. pulling on the yoke). From the Boeing 737 NG FCTM (6.10 Landing):

When the threshold passes under the airplane nose and out of sight, shift the visual
  sighting point to the far end of the runway. Shifting the visual sighting point assists
  in controlling the pitch attitude during the flare. Maintaining a constant airspeed
  and descent rate assists in determining the flare point. Initiate the flare when the
  main gear is approximately 20 feet above the runway by increasing pitch attitude
  approximately 2° - 3°. This slows the rate of descent.
After the flare is initiated, smoothly retard the thrust levers to idle, and make small
  pitch attitude adjustments to maintain the desired descent rate to the runway.
  Ideally, main gear touchdown should occur simultaneously with thrust levers
  reaching idle. A smooth thrust reduction to idle also assists in controlling the
  natural nose-down pitch change associated with thrust reduction. Hold sufficient
  back pressure on the control column to keep the pitch attitude constant. A
  touchdown attitude as depicted in the figure below is normal with an airspeed of
  approximately VREF plus any gust correction.

The flaps are set much earlier during the approach phase. They are not changed any more during the landing phase.

I don't know if your question relates to the approach phase or the flare. The later as explained above has to do with the elevator, the former i.e for the approach phase you will notice that airliners and even more so fighter jets come on the approach indeed with a high noze up attitude. That has to do with swept wings. Swept wings allow an aircraft to fly faster by retarding the speed at wich the wings will become supersonic. That's all fine, but the problem with that is (amongst other ones): it will reduce the lift generated by the wing therefore forcing the aircraft to fly at a higher angle of attack during the approach. Hence the noze up attitude of the plane during that phase.

For landing an airplane has to slow down. When looking at the lift equation,
$$L=\frac{1}{2}c_L(\alpha)\rho v^2A$$
We find that, to get constant lift $L$ with lower speed $v$ we need to increase either $c_L(\alpha)$ or wing surface area $A$ (we can't change the air density $\rho$).
Note the explicit dependency of the lift coefficient on the angle of attack $\alpha$. We can increase the angle of attack by pitching up, which is why planes generally have a nose high attitude on landing.
Flaps change either the lift coefficient for constant $\alpha$, the wing surface area, or both. This helps to reduce the required angle of attack, so the the pitch attitude may be reduced as well.

Flaps help to increase the lift at low speed, allowing the aircraft to fly at a lower than cruise speed speed.
The pitch up is caused by the elevator on the rear wing.


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Did older Airliners use a pitot-static system?
Aircraft like the B707, how would the aircraft gather speed and altitude data? And if they used pitot static system by that time, was there ever anything else that gathered the speed data?

Remember, pitot static systems have been around since well before jet aircraft.

They used the same kind of pitot probes and static ports as modern aircraft, but prior to the 70s they didn't use Air Data Computers  that processed the pitot static information in a central location for electronic distribution to other systems that needed the data (that had to wait for the Integrated Circuit and Microprocessor revolutions of the 60s).
Prior to that the pitot and static pressure was routed directly to the instruments and devices that needed to measure it, so you had the plumbing itself routed to both the pitot static instruments and electronic devices that needed it, pretty much like with light aircraft, but with way more plumbing.  The adoption of ADCs reduced the plumbing requirements to just that required between the probes and ports and the ADCs.
Computations and conversions of pressure data (like deriving Mach#) were done by analog mechanical or electronic means directly within the instruments themselves.
So, an airplane like a 707 in the late 50s would have lots and lots of low pressure pneumatic plumbing running up behind the instrument panels and to various analog computing devices in the avionics bay.